/******************************************************************************
 *                                                                            *
 * Copyright (c) 1999-2003 Wimba S.A., All Rights Reserved.                   *
 *                                                                            *
 * COPYRIGHT:                                                                 *
 *      This software is the property of Wimba S.A.                           *
 *      This software is redistributed under the Xiph.org variant of          *
 *      the BSD license.                                                      *
 *      Redistribution and use in source and binary forms, with or without    *
 *      modification, are permitted provided that the following conditions    *
 *      are met:                                                              *
 *      - Redistributions of source code must retain the above copyright      *
 *      notice, this list of conditions and the following disclaimer.         *
 *      - Redistributions in binary form must reproduce the above copyright   *
 *      notice, this list of conditions and the following disclaimer in the   *
 *      documentation and/or other materials provided with the distribution.  *
 *      - Neither the name of Wimba, the Xiph.org Foundation nor the names of *
 *      its contributors may be used to endorse or promote products derived   *
 *      from this software without specific prior written permission.         *
 *                                                                            *
 * WARRANTIES:                                                                *
 *      This software is made available by the authors in the hope            *
 *      that it will be useful, but without any warranty.                     *
 *      Wimba S.A. is not liable for any consequence related to the           *
 *      use of the provided software.                                         *
 *                                                                            *
 * Class: Ltp.java                                                            *
 *                                                                            *
 * Author: James LAWRENCE                                                     *
 * Modified by: Marc GIMPEL                                                   *
 * Based on code by: Jean-Marc VALIN                                          *
 *                                                                            *
 * Date: March 2003                                                           *
 *                                                                            *
 ******************************************************************************/

/* $Id: Ltp.java,v 1.2 2004/10/21 16:21:57 mgimpel Exp $ */

/* Copyright (C) 2002 Jean-Marc Valin 

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:
   
   - Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
   
   - Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
   
   - Neither the name of the Xiph.org Foundation nor the names of its
   contributors may be used to endorse or promote products derived from
   this software without specific prior written permission.
   
   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

package org.xiph.speex;

/**
 * Abstract class that is the base for the various LTP (Long Term Prediction)
 * Quantisation and Unquantisation methods.
 * 
 * @author Jim Lawrence, helloNetwork.com
 * @author Marc Gimpel, Wimba S.A. (mgimpel@horizonwimba.com)
 * @version $Revision: 1.2 $
 */
public abstract class Ltp
{
  /**
   * Long Term Prediction Quantification.
   * @return pitch
   */
  public abstract int quant(float[] target, float[] sw, int sws, float[] ak, float[] awk1, float[] awk2,
                            float[] exc, int es, int start, int end, float pitch_coef, int p, 
                            int nsf, Bits bits, float[] exc2, int e2s, float[] r, int complexity);

  /**
   * Long Term Prediction Unquantification.
   * @param exc - Excitation
   * @param es - Excitation offset
   * @param start - Smallest pitch value allowed
   * @param pitch_coef - Voicing (pitch) coefficient
   * @param nsf - Number of samples in subframe
   * @param gain_val
   * @param bits - Speex bits buffer.
   * @param count_lost
   * @param subframe_offset
   * @param last_pitch_gain
   * @return pitch
   */
  public abstract int unquant(float[] exc, int es, int start, float pitch_coef,  
                              int nsf, float[] gain_val, Bits bits,
                              int count_lost, int subframe_offset, float last_pitch_gain);

  /**
   * Calculates the inner product of the given vectors.
   * @param x - first vector.
   * @param xs - offset of the first vector.
   * @param y - second vector.
   * @param ys - offset of the second vector.
   * @param len - length of the vectors.
   * @return the inner product of the given vectors.
   */
  protected static float inner_prod(float[] x, int xs, float[] y, int ys, int len)
  {
    int i;
    float sum1=0,sum2=0,sum3=0,sum4=0;
    for (i=0;i<len;)
    {
      sum1 += x[xs+i]*y[ys+i];
      sum2 += x[xs+i+1]*y[ys+i+1];
      sum3 += x[xs+i+2]*y[ys+i+2];
      sum4 += x[xs+i+3]*y[ys+i+3];
      i+=4;
    }
    return sum1+sum2+sum3+sum4;
  }

  /**
   * Find the n-best pitch in Open Loop.
   * @param sw
   * @param swIdx
   * @param start
   * @param end
   * @param len
   * @param pitch
   * @param gain
   * @param N
   */
  protected static void open_loop_nbest_pitch(final float[] sw,
                                              final int swIdx,
                                              final int start,
                                              final int end,
                                              final int len,
                                              final int[] pitch,
                                              final float[] gain,
                                              final int N)
  {
    int i, j, k;
    /*float corr=0;*/
    /*float energy;*/
    float[] best_score;
    float e0;
    float[] corr, energy, score;

    best_score = new float[N];
    corr = new float[end-start+1];
    energy = new float[end-start+2];
    score = new float[end-start+1];
    for (i=0; i<N; i++) {
      best_score[i]=-1;
      gain[i]=0;
      pitch[i]=start;
    }
    energy[0]=inner_prod(sw, swIdx-start, sw, swIdx-start, len);
    e0=inner_prod(sw, swIdx, sw, swIdx, len);
    for (i=start; i<=end; i++) {
      /* Update energy for next pitch*/
      energy[i-start+1] = energy[i-start] + sw[swIdx-i-1]*sw[swIdx-i-1] - sw[swIdx-i+len-1]*sw[swIdx-i+len-1];
      if (energy[i-start+1] < 1)
        energy[i-start+1]=1; 
    }
    for (i=start; i<=end; i++) {
      corr[i-start]=0;
      score[i-start]=0;
    }

    for (i=start; i<=end; i++) {
      /* Compute correlation*/
      corr[i-start]=inner_prod(sw, swIdx, sw, swIdx-i, len);
      score[i-start]=corr[i-start]*corr[i-start]/(energy[i-start]+1);
    }
    for (i=start; i<=end; i++) {
      if (score[i-start] > best_score[N-1]) {
        float g1, g;
        g1 = corr[i-start]/(energy[i-start]+10);
        g = (float) Math.sqrt(g1*corr[i-start]/(e0+10));
        if (g>g1)
          g=g1;
        if (g<0)
          g=0;
        for (j=0; j<N; j++) {
          if (score[i-start] > best_score[j]) {
            for (k=N-1; k>j; k--) {
              best_score[k]=best_score[k-1];
              pitch[k]=pitch[k-1];
              gain[k] = gain[k-1];
            }
            best_score[j]=score[i-start];
            pitch[j]=i;
            gain[j]=g;
            break;
          }
        }
      }
    }
  }
}